With the development of application-based smart devices such as smartphones and smart pads and the development of mobile communication technologies and Internet communication technologies, people can easily and simply use various services through the Internet and the applications.
Most services require user authentication before the services are provided to the user because a third party may use the services by stealing the user's identity.
While user authentication can be performed with the user's identification card or driver's license in a presence of the user in the offline environment, in the online environment where the service provider does not come into contact with users, different methods of user authentication are needed.
Accordingly, various technologies have been developed and applied to verify the user's identity of the personal information entered for use of the services.
Such technologies may include an Internet Personal Identification Number (I-PIN) authentication, Short Message Service (SMS) authentication, Automatic Response System (ARS) authentication, and electronic signature or digital signature authentication.
According to the SMS authentication, for example, the service server may transmit an authentication code to a mobile terminal (i.e., a mobile phone or a smartphone) of the user through SMS so that the user may input the received authentication code into a web page or an application program, and verify the user by determining whether the authentication code entered by the user matches the authentication code registered for the mobile terminal.
However, the above-described technologies have a risk of being used illegally by a third party when the mobile terminal is lost or personal information is leaked.
Therefore, there is a trend toward hybrid methods that employ two or more of the above technologies to enhance user security, which is increasing demand for additional technologies for more accurate user authentication.
One of such technologies being developed for enhancing the security can be handwritten signature authentication, which is one of biometric information reflecting personal characteristics of each user.
The handwritten signature authentication technology may be divided into two categories: image comparison method that examines match rates of the images of handwritten signatures and a behavioral characteristics data comparison method that compares behavioral characteristics data when a signer handwrites a signature.
Typically, a handwritten signature authentication method employing the image comparison method has a risk that the third party copies the signature image of the user. In this case, the system may determine that the copied signature of the third party matches the actual signature of the user.
Because of such a problem, the behavioral characteristics data comparison method is preferred in a handwritten signature authentication system.
A handwritten signature authentication system employing the behavioral characteristics data comparison method performs handwritten signature authentication by extracting and storing the characteristics of the user's signature patterns, such as pressure, speed, intersection points, and inflection point angles. However, the behavioral characteristics comparison method also often leads to cases where a third party copies the behavioral characteristics to some extent when copying a handwritten signature image. In some cases, the traditional handwritten signature authentication system determines that two signatures match on the basis of similar behavioral characteristics even when the images of the two signatures are completely different.
Therefore, there is a demand for a method for a handwritten signature authentication system that can distinguish handwritten signatures more accurately, thereby enhancing security with higher levels of handwritten signature recognition and authentication accuracy.